Bead seating apparatus which injects air into a tubeless tire between the tire bead and the rim of the associated wheel is well known. See, for example, U.S. Pat. Nos. 3,522,469; 3,675,705; and 3,814,163 which describe such bead seaters. In this type of bead seater at the same time that air is supplied to the tire through the usual inflation valve high velocity air is injected into the tire between the bead and the rim. Air is thus supplied to the tire at a rate which is faster than the rate at which air can escape from the tire, wherefore the tire becomes pressurized and the bead is forced into sealing engagement with the rim. Thereafter, the high velocity air stream is terminated and the air supplied through the usual tire valve fully inflates the tire.
While these prior art bead seaters have performed satisfactorily, they have been relatively large and cumbersome and are relatively noisy. Moreover, any given machine has not functioned well with all sizes of tires and with all tire and wheel combinations. Indeed, it is extremely difficult and in some cases impossible to seat the beads of some tire and wheel combinations with the bead seaters now on the market.
Some of the aforementioned prior art bead seaters have employed rings of orifices surrounding the bead from which high velocity air is injected into the tire along the entire periphery of the bead to be seated. Attempts to reduce the noise from machines of this type have not been successful. In other bead seaters air has been injected between the tire bead and the rim from a plurality of orifices arranged in an arc. Noise is still a problem.
In some of these prior art bead seaters the air is injected down into the tire from orifices disposed above the tire while in others the air is injected up from the bottom as, for example, in the bead seating apparatus shown in U.S. Pat. No. 3,786,852.
When the air is injected from the bottom it tends to follow the surface of the table on which the wheel rests and thus to be deflected by the edge of the wheel rim which creates turbulence in the area between the rim and the bead and thereby impedes the smooth flow of air into the tire and generates additional high frequency noise. On the other hand, locating the bead seating manifold and orifices above the tire has made it more difficult to place the wheels and tires on the associated tire changer as well as to remove the inflated wheels and tires from the tire changer, and has made the noise problem more difficult to correct.